Standard and Poor's today upgraded Spain's credit rating a notch to 'BBB' from 'BBB-', saying structural reforms have improved economic growth and outlook.

Reforms undertaken since 2010 have boosted economic growth and competitiveness, the agency said, adding that its outlook for the country was stable.

Spain, the euro zone's fourth-biggest economy, was plunged into a double-dip recession in 2008 when a decade-long property bubble burst, wiping out millions of jobs. 

Spain's economy emerged slowly from a two-year downturn in mid-2013, posting 0.4% quarterly growth - the fastest pace in six years - in the first three months of this year.